<?php
abstract class Register {
    const CLIENT = 'client';
    const SERVER = 'server';
    protected static $store = array();

    public static function set($key, $value) {
        self::$store[$key] = $value;
    }
    public static function get($key)
    {
        return isset(self::$store[$key]) ? self::$store[$key] : null;
    }
}